diff --git a/munin/manifests/init.pp b/munin/manifests/init.pp
index d6d46fd..786418a 100644
--- a/munin/manifests/init.pp
+++ b/munin/manifests/init.pp
@@ -135,7 +135,7 @@ define munin::snmpnode($snmp_community="public", $snmp_version="2") {
 }
 
 
-# Add new custom munin plugin.
+# Add new munin plugin or plugin configuration.
 #
 # === Parameters
 #
@@ -144,9 +144,9 @@ define munin::snmpnode($snmp_community="public", $snmp_version="2") {
 #   $enable:
 #       Set to false to disable plugin.
 #   $source:
-#       Source path for the plugin.
+#       Source path of the plugin.
 #   $config:
-#       Source path of plugin configuration file. Defaults to none.
+#       Source path of plugin configuration file.
 #
 # === Sample usage
 #
@@ -158,10 +158,6 @@ define munin::snmpnode($snmp_community="public", $snmp_version="2") {
 define munin::plugin($enable=true, $source=undef, $config=undef) {
 
     if $enable == true {
-        if ! $source {
-            fail("Must define source parameter for Munin::Plugin[${name}]")
-        }
-
         case $::operatingsystem {
             "openbsd": {
                 $plugindir = "/usr/local/libexec/munin/plugins"
@@ -171,33 +167,34 @@ define munin::plugin($enable=true, $source=undef, $config=undef) {
             }
         }
 
-        file { "${plugindir}/${name}":
-            ensure  => present,
-            mode    => "0755",
-            owner   => "root",
-            group   => $::operatingsystem ? {
-                "openbsd" => "wheel",
-                default   => "root",
-            },
-            source  => $source,
-            notify  => Exec["munin-node-configure"],
-            require => Package["munin-node"],
+        if $source {
+            file { "${plugindir}/${name}":
+                ensure  => present,
+                mode    => "0755",
+                owner   => "root",
+                group   => $::operatingsystem ? {
+                    "openbsd" => "wheel",
+                    default   => "root",
+                },
+                source  => $source,
+                notify  => Exec["munin-node-configure"],
+                require => Package["munin-node"],
+            }
         }
 
-        file { "/etc/munin/plugin-conf.d/${name}":
-            ensure  => $config ? {
-                undef   => absent,
-                default => present,
-            },
-            mode    => "0644",
-            owner   => "root",
-            group   => $::operatingsystem ? {
-                "openbsd" => "wheel",
-                default   => "root",
-            },
-            source  => $config,
-            notify  => Exec["munin-node-configure"],
-            require => Package["munin-node"],
+        if $config {
+            file { "/etc/munin/plugin-conf.d/${name}":
+                ensure  => present,
+                mode    => "0644",
+                owner   => "root",
+                group   => $::operatingsystem ? {
+                    "openbsd" => "wheel",
+                    default   => "root",
+                },
+                source  => $config,
+                notify  => Exec["munin-node-configure"],
+                require => Package["munin-node"],
+            }
         }
     } else {
         file { "/etc/munin/plugin-conf.d/${name}":